package org.apache.commons.httpclient does not exist

Hello thereI just tried to test YahooWebServiceGet.java and YahooWebServiceParseResults.java in netbeans. To do so I included all the jar files from httpcomponents-client-4.0.1/lib/ in the netbeans project classpath. As far as it seems, this jar files do not include package org.apache.commons.httpclient because to start with I am getting errors at these sentences: